Engine-governor



(No Model) 2 SheetsSheet l. W. DENNIS.

ENGINE GOVERNOR.

No. 435,923. Patented Sept. 9, 1890.

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(No Model.) 2 Sheets-Sheet 2.

W. DENNIS. ENGINE GOVERNOR.

No. 435,923. Patented Sept. 9, 1890.

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UNITED STATES PATENT OFFICE.

\VILBER DENNIS, OF MINNEAPOLIS, MINNESOTA.

ENGINE-GOVERNOR.

SPECIFICATION forming part of Letters Patent No. 435,923, datedSeptember 9, 1890.

Application filed February 14, 1890. Serial No. 340,499- (No model.)

To all whom it may concern.-

Be it known that I, VILBER DENNIS, of Minneapolis, in the county ofHennepin and State of Minnesota, have invented certain new and usefulImprovements in Engine- Governors, of which the following is aspecification.

My invention relates to improvements in automatic governors forsteam-engines, and to that class of governors which by changing theposition of the eccentric from which the motion of the valve or valvesis derived cause the admission of steam to the cylinder of the engine tobe cut off at different points in the stroke. Governors of this generalclass have long been known. In one form of such governor the centrifugalforce of weights revolving with the shaft is resisted by the extensionof springs, which tend to pull the weights inward. Said weights beingpivoted at or near one end, can be moved radially on their pivotalpoints to and from the shaft. The centrifugal force of the weights beingopposed to the force of the springs, and being dependent upon the speedof the engine-shaft, there is a certain speed at which the two opposingforces are in equilibrium, any increase in speed causing an increase ofcentrifugal force and a corresponding outward movement of the weights,while a decrease of speed causes a loss of centrifugal force when thesprings pull the weights inward. By means of suitable connecting devicesbetween the weights and eccentric the eccentric is moved into a properposition to cut off the admission of steam at an earlier or later pointin the stroke corresponding with the inward or outward movement of theweights as the speed is changed.

I use the same general arrangement in my invention, wherein the motionof the weights during the establishment of an equilibrium between thetwo opposing forces described is the ultimate means by which theeccentric is adjusted and the speed of the engine controlled. Adifficulty has been found in making such governors sufficiently quick inaction without producing an overaction, whereby too great change in theadjustment of the cut-off mechanism is produced. Owing to friction andinertia of the moving parts the weights stay at an inward position untilthe speed is too fast, then move outward too far, owing to theirmomentum and increased centrifugal force due to increase of speed. Thismovement causes the eccentric to assume a position whereby too early acut-off is given, thus reducing the speed of the engine below the properspeed. Then the weights are forced inward too far. This causes too latecut-01f and the speed is increased again. These vibrations of speedcontinue and are greatly detrimental to the satisfactory workings of theengine and machinery which may be driven by it. Many different deviceshave been tried to obviate this irregularity. My invention providesmeans for preventing these vibrations, and at the same time renders thegovernor much quicker in the adjustment of its parts to meet the suddenchanges in speed under sudden variations of load or steainpressure, allof which is hereinafter described, and particularly pointed out in theclaims.

In the accompanying drawings, forming a part of this specification,Figure 1 is an elevation of the governing mechanism as applied to aneccentric to vary the amount of its eccentrieity with eccentric and rod.Fig. 2 is asec tional view of Fig. l on line 00 0c of Fig. 1. Fig. 3 isan elevation showing the eccentric removed. Fig. i is a sectional viewof Fig. 3 on line y y. Fig. 5 is an elevation showing the governorapplied to an eccentric to vary the angular advance of the same. Fig. 6is a sectional view of Fig. 5 on line .2 a.

It should be understood thatthere isa crank, piston, cylinder, and theother essential parts of a steam-engine, and that the valves and otherparts are so arranged and proportioned that the point in each stroke ofthe piston at which admission of steam to the cylinder is stopped or cutoff may be varied within wide limits by varying the amount ofeccentricity of the eccentric, as shown in Figs. 1 and 2, or by apartial rotation of the eccentric on the shaft, thereby changing itsangular advance, as shown in Figs. 5 and 6.

In the drawings, 2 represents a case or rim having the arms 3 and thehub l rigidly secured to the shaft 5 in any suitable manner. The hub iis preferably set off, as shown, to

allow room for the proper reception of certain parts of the governorWithin the rim 2. 5 represents the shaft of the engine whose speed it isdesired to regulate by this governor.

7 is an arm, preferably formed with a hub 8 in its center, and with itsends 9 enlarged, so as to possess considerable weight. 7 The hub 8 isadapt-ed to rotate upon the shaft 5, so as to allow free movement of thearm 7 upon said shaft.

10 represents suitable weights pivoted within the rim 2 to lugs 11 bymeans of the pins 12. These pins passing through one end of each weightallow of the movement of the loose end of each toward or away from theshaft 5.

Connecting the weights 10 with the arm 7 are the connecting-rods 13, oneend of each secured to the arm 7 by means of the pin 14, their oppositeends being pivotally connected to the weights 10 by means of the pins15; also secured to the weights 10 are the springs 17, adj ustablysecured at their opposite ends by tension-bolts 18, projecting throughlugs 19, formed upon arms of the wheel 2 and held in place by means ofnuts 20. The tension of the springs may thereby be increased ordiminished, requiring a greater or less force to throw the weights 10outward.

In Figs. 1 and 2, 23 represents a shiftingeccentric carrying theeccentric valve-rod 25 by means of the strap or ring 26, which as theeccentric revolves operates the valve by means of the eccentric-rod. Theeccentric 23 is provided with the slotted opening 29, permittin g it tobe shifted across the shaft 5 upon the arm 30, pivotally secured to therim 2 by means of the bolt 31 passing through said arm and the lug 32 ofthe rim 2. The shifting of the eccentric, throwing its center fartherfrom or nearer to the center of the shaft 5, increases or diminishes itseccentricity. WVhen the eccentric is so situated on the shaft 5 as to benear one end of the slot 29, the rotation of the shaft does not move thevalve far enough to admit steam to the cylinder; but when shifted sothat the shaft 5 is near the other end of the curved slot 23 full steamis admitted by the valve. When the eccentric is in an intermediateposition, it will move the valve properly to cut off the admission ofsteam to the cylinder at an earlier point in the stroke. A lug 35 formedupon the eccentrio is connected with the arm 7 by means of link 36 andpins 37 and 38. A partial rotation of the arm 7 around the shaft 5 willcause the eccentric 23 to be moved across the shaft by means of the link36 and its connections, as described. Each position of the arm 7coincides with a certain position of the eccentric 23. In practicaloperation the connection between the arm 7 and eccentric 23 is so madethat the partial rotation of the arm 7 around the shaft 5 in the samedirection in which the shaft revolves will move the eccentric 23 so thatit will have a greater throw or amount of eccentricity, therebyoperating the valve so as to cause a later point of cut-ofi and agreater amount of steam to enter the cylinder during each stroke. Anopposite movement of the arm 7 moves the eccentric so as to cause thevalve to out off steam from the cylinder at a point earlier in thestroke, causing a less amount of steam to enter the cylinder during eachstroke.

The operation of this governor is as follows: Steam being admittedto'the cylinder the engine starts, and as its speed increases thecentrifugal force of the weights 10 causes them to move out, drawing arm7 around the shaft, causing the'valve to out oif shorter by means of theconnecting devices previously described. WVhen the speed has increasedto that point where the centripetal force furnished by the tension ofthe springs 17 equals the centrifugal force of the weights 10, the

increase of speed of the engine will cease and.

the speed of the engine remain constant until a change of load orsteam-pressure occurs. Underslight variations, either of loadorsteampressure, the action of the weights 10 and spring 17 issufficient to govern the engine, the inertia of arm 7 providing means toprevent any vibrations which might otherwise ensue from excessivevalve-friction or other disturbing causes. \Vhen a heavyload is suddenlyput upon the engine, the speed is lessened until the governor shallhaveadjusted the position of the eccentric to admit the properamount ofsteam to carry the increased load at the requisite speed. Ordinarygovernors of this class delay action until the centrifugal weights losepart of their force sufficient for force of the springs to overcome theinertia of the weights, and also the frictional resistance of thegovernor before they can adjust themselves. This often requiressufficient time to allow of great variation of speed. With my governorany sudden decrease of speed is met by the action of the arm 7, whichwill by its momentum continue to revolve without a decrease of speed fora short space of time, and during this time will have moved so that itsposition with relation to the remainder of the governor is ahead of thatwhich it occupied when the speed was decreased. This movement of the arm7, in combination with the action of the springs 17 on the weights 10,results in such a quick adj ust ment of the supply of steam to theenginecylinder that little or practically no decrease of speed occurs.The same quickness of adjustment occurs when the opposite conditions arepresented. The whole or greater part of the load being instantly takenoff the engine its speed will be immediately accelerated. The arm 7 notpartaking of this immediate acceleration because of its inertia, dragsbehind the rest of the governor and shaft, and through its connectionsacts with the increased centrifugal force of the weights 10 to adjustthe eccentric so that a less amount of steam may enter the cylindercorresponding to the decrease of load on the engine.

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Figs. 5 and 6 show the arrangement of this governor as applicable to aneccentric for varying its angular advance by partially rotating itaround the shaft, whereby the position of the cut-off valve or valvesoperated by the eccentric is so changed with reference to the positionof other valve or valves as to cause the admission of steam to thecylinder of the engine to be cut off at different points in the stroke,such point of cut-oif being dependent upon the angular advance of theeccentric which is controlled by the governor. This application of thegovernor requires but small changes from the form in which it has beenpreviously, as described in the specification.

The case 2, arm 7, weights 10, springs 17, and their connections,forming the governing mechanism,are identical with those hereinbeforedescribed, with a cut-off eccentric having a variable amount ofeccentricity.

In Figs.5 and 6, 45 is the eccentric, formed upon a sleeve or collar 46,bored to fit the shaft 5, so as to allow of free motion thereon. Sleeve46 has upon it projecting lugs 47 and 48, each with a pin 49 projectingtherefrom. Upon the inner circumference of the rim of the governor caseor rim 2 is aprojecting lug 50, upon which is pivoted, by means of thepivot 51, a rocker-arm or lever 52. This lever is provided with twopivot-bolts 53, one near each end and equally distant from the centralpivot 51. The rod connects the rocker-arm 52 with the arm 7 by means ofthe bolt 53 in the rocker-arn1 52 and 56 in arm 7, thereby communicatingany movement of arm 7 to rocker arm 52, from Which rods 57, connectedwith the pins 53 on the arm 52 at one end, and with pins it) upon thesleeve 46 at their other ends, transform any vibratory motion of therocker-arm into a partial rotation of the sleeve 46 and eccentric 45, sothat the action of the governor varies the angular advance of theeccentric, thereby varying the point of cutoff, as previously described,centripetal force, inertia, momentum, and centrifugal forceactingtogether to produce the adjustments in the same manner as in theformer construction.

I claim as my invention- 1. In an engine-governor, the combination,

with a wheel adapted to carry a part of the governing mechanism andrigidly secured to the shaft whose speed is to be governed, centrifugalweights pivotally secured to said wheel, and tension-springs adjustablysecured to said weights and to said wheel, of a weighted arm looselyjournaled upon the same shaft and pivotally connected to saidcentrifugal weights by inelastic connections, and suitable connectionsfrom said weighted arm, whereby an eccentric may be shifted across orpartially rotated around said shaft, for the purposes specified.

2. I11 an engine-governor, the combination, with a wheel adapted tocarry a part of the governing mechanism and rigidly secured to the shaftwhose speed is to be governed, centrifugal weights pivotally secured tosaid wheel, tension-springs adj ustably secured to said weights and tosaid wheel, and an eccentric adapted to be rotated about said shaft, ofa weighted arm loosely journaled upon said shaft and pivotally connectedto said centrifugal weights, a rocker-arm pivotally secured at itscenter to said wheel, a connecting-rod pivotally connecting saidweighted arm with one end of said rocker-arm, and connecting-rodspivotally connecting said rockerarm with said eccentric, substantiallyas described, and for the purpose specified.

3. The combination, with a wheel adapted to carry a part of thegoverning mechanism and rigidly secured to the shaft whose speed is tobe governed, centrifugal weights pivotally secured to said wheel, andtension-springs adj ustably secured to said weights and to said wheel,of a weighted arm loosely journaled upon said shaft and pivotallyconnected to said weights, and a slotted eccentric pivotally connectedto the rim of said wheel and to said weighted arm and adapted to beshifted across or partially rotated around said shaft, for the purposespecified.

In testimony whereof I have hereunto set my hand this 8th day ofFebruary, 1890.

WILBER DENNIS. In presence of A. 0. PAUL, A. M. GASKILL.

